This picture was suprisingly difficult to take and required
several attempts to get it right. A colour version is very
effective.

The first problem is that a welding arc is VERY dangerous and can
PERMENANTKLY damage eyes. I could, thus, not look at the subject.

The first attempts used the apparently bright arc as a light
source. The results were very under exposed indeed.

This is how it was done...

The man was set up and the camera fitted to a tripod. The lens, a
short telephoto, was focused on the work piece. A flash was
positioned off camera, and connected to the camera with an
extension lead. The flash is low and to the left, pointing up at
the mans face mask. The flash exposure was calculated. I used a
flash meter, but dividing the distance from flash to mask INTO
the flash guide number would give the correct aperture.

For example,   distance = 2 metres
			GN       = 22 (in metres)

Thus, aperture to set for correct exposure to flash is f11. Set
this exposure, turn your back on the welder and ask him to start
welding. When he begins, make the exposure.

I tried several versions by changing the aperture without turning
round.